There are altogether 123 PNe (besides 26 variables belonging to the objects, which were removed from the list of PNe) listed in the GCVS + supplementary lists (Kholopov et al., 1985-1990) or in the catalogue of suspected variable stars (Kholopov et al., 1982). The fact that 54% of the above objects were classified as suspected variables reflects the difficulties of recognizing PNe as variable objects (mainly due to the disturbing effect of the nebulae). Moreover 4 objects of the 56 known variables appeared to be constant. The remaining variables are in most cases symbiotic variables of Z And type (n=10) and unique objects (n=8). Only 3 objects (A 46, A 63, BE UMa) are Algol-type eclipsing binaries. In the following summary all variable PNe (also misclassified objects) are listed including their type of variability according to GCVS. The main purpose of this summary is to encourage observers to monitor the PNe in order to find further variables, which would be very desirable.